CN113353964A - Method for preparing anhydrous calcium sulfate from industrial solid waste gypsum - Google Patents
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- C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
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Abstract
The invention discloses a method for preparing anhydrous calcium sulfate from industrial solid waste gypsum, which takes the industrial solid waste gypsum as a raw material, mixes a plurality of industrial solid waste gypsum with acid solution for pulping, adds a certain amount of organic solvent, processes the mixture for a period of time under normal pressure and mild temperature, separates the solid-liquid mixture after the reaction is finished, returns the obtained filtrate to continue to react with the waste gypsum, and washes the filter cake to obtain the high-purity anhydrous calcium sulfate. The industrial solid waste gypsum with high impurity content can be realized without high temperature, and the impurities can be enriched and removed in the process. The prepared anhydrous gypsum has the excellent performances of high purity, high whiteness, uniform particle size and the like. The low-carbon circulation process has low energy consumption, does not produce secondary pollution and is beneficial to large-scale production. Can realize the purpose of preparing high-quality anhydrous calcium sulfate from industrial solid waste gypsum, finds a substitute technology for increasingly reduced high-grade gypsum resources, and has good economic benefit and wide industrial application prospect.
Description
Technical Field
The invention relates to a comprehensive utilization technology of industrial solid waste resources, in particular to a method for preparing anhydrous calcium sulfate from industrial solid waste gypsum in resource recycling of industrial waste.
Background
The industrial solid waste gypsum is an industrial byproduct which is generated by chemical reaction in industrial production and takes calcium sulfate as a main component. According to the types, the gypsum can be divided into phosphogypsum, salt gypsum, desulfurized gypsum, titanium gypsum, fluorgypsum, citric acid gypsum and the like. The industrial solid waste gypsum accumulation in China is large, and the discharge amount is increased year by year. The stockpiling of the solid waste gypsum not only occupies a large amount of land, but also causes serious harm to the ecological environment. The urgency of disposal and resource utilization of industrial solid waste gypsum is urgent. As a novel inorganic material, compared with other powder materials, the anhydrous calcium sulfate has a plurality of excellent physical and chemical properties such as high strength, high modulus, high dielectric strength, wear resistance, high temperature resistance, corrosion resistance, good infrared reflectivity, easy surface treatment, strong affinity with high polymer, no toxicity and the like, has the lowest price in the powder, has incomparable cost performance with other powder, has a very wide application range, is a green environment-friendly material with excellent performance and low price, and has strong market competitiveness, so the anhydrous calcium sulfate is often used as a filler of high polymer materials, not only can endow the material with certain rigidity and size stability, but also can improve the thermal stability and wear resistance of the material and reduce the cost.
At present, most of the anhydrous calcium sulfate preparation methods are prepared by calcining natural gypsum or industrial by-product gypsum at high temperature, wherein the calcining temperature is generally higher than 550 ℃, and the energy consumption requirement is high.
Patent CN103396023A discloses a preparation process of anhydrous calcium sulfate, which is to rapidly dehydrate calcium sulfate dihydrate powder under the action of high-temperature fuel gas at 400-950 ℃ to produce calcium sulfate powder. The anhydrous calcium sulfate prepared by the process technology still has the defects of product performance and technical defects, and the product has poor dispersibility and high energy consumption.
In patent CN101033118A, phosphogypsum is calcined by adopting a new process of mixing external calcination (indirect calcination) and internal calcination (direct calcination), so that gypsum powder meeting the national standard is produced, but because phosphoric acid and fluoride volatilize during calcination, the environment is polluted, equipment is corroded, the energy consumption cost of high-temperature calcination is high, and the application is greatly limited. Meanwhile, the impurities with the largest content in the phosphogypsum are quartz, and the calcining process cannot remove the quartz impurities, so that a high-white and high-purity high-quality gypsum product cannot be produced by the calcining method.
The patent CN101671848A provides a preparation method of anhydrous calcium sulfate whiskers, wherein the process conditions are that calcium sulfate dihydrate crystals are firstly dispersed into a water solution containing a surfactant under the low temperature condition, then hydrothermal reaction is carried out for a period of time under the condition of 100-250 ℃, finally, the hemihydrate gypsum whiskers obtained through the hydrothermal reaction are mixed with an inorganic solvent and then are roasted for 0.5-6 h under the high temperature of 200-800 ℃, and the anhydrous calcium sulfate whiskers are finally prepared, and the content of the anhydrous calcium sulfate whiskers in the final product can reach more than 95%. However, the preparation process of the method for preparing anhydrous calcium sulfate whisker described in the patent relates to three levels of low temperature, medium temperature and high temperature, wherein the high temperature can reach 800 ℃ at most, the energy consumption in the whole preparation process is more, and the preparation process is more complex, thus being not beneficial to large-scale popularization and application.
Patent CN103014869A relates to a controllable preparation method of anhydrous calcium sulfate whisker, the main preparation process is similar to patent CN101671848A, the difference is that the patent firstly carries out normal temperature acidification treatment on calcium sulfate dihydrate to obtain high-activity calcium sulfate hemihydrate, then carries out hydrothermal reaction to prepare calcium sulfate hemihydrate whisker, and finally prepares the anhydrous calcium sulfate whisker by roasting. The two methods and the flow for preparing the anhydrous calcium sulfate crystal whisker are complicated and are difficult to put into practical production.
The schemes can partially relieve the current situation of large-scale stacking of industrial solid waste gypsum, but the problems are still more. Although the treatment processes can eliminate the adverse effects of some harmful impurities to a certain extent, the treatment processes have large investment, high energy consumption and difficult solution of secondary pollution, and the quality of the treated solid waste gypsum is still low. Therefore, in order to solve the practical problem of resource utilization of the industrial solid waste gypsum, a new method is urgently needed to be found from the aspects of technology, cost, product quality and the like.
Disclosure of Invention
The invention provides a method for preparing anhydrous calcium sulfate from industrial solid waste gypsum, which can greatly reduce energy consumption without high-temperature calcination, can purify the anhydrous calcium sulfate with high purity, good whiteness, uniform particle size and other excellent performances, and can prepare the anhydrous calcium sulfate from the anhydrous calcium sulfate after the solid waste gypsum is treated with extremely high added value.
The invention adopts the following specific technical scheme for solving the technical problems: the method for preparing anhydrous calcium sulfate from industrial solid waste gypsum is characterized by comprising the following steps:
the method comprises the following steps: drying, crushing, grinding and sieving industrial solid waste gypsum to obtain powder with the particle size of less than 100 meshes for later use, enriching screen residues, and calcining the powder into a glass building material;
step two: mixing the powder with the granularity of less than 100 meshes obtained in the step one with hydrochloric acid, adding an organic solvent, stirring, heating, and continuing to react for 1-6 hours after the temperature of the mixture is raised to 70-90 ℃;
step three: standing the suspension obtained in the step two to separate solid from liquid, wherein the upper layer is a liquid phase layer containing impurities, and the lower layer is a solid precipitation layer of purified gypsum;
step four: separating the solid-liquid mixture obtained in the step three, wherein a liquid phase layer and a solid precipitate are respectively separated;
step five: filtering the impurity-containing liquid phase layer obtained in the fourth step to remove residues, enriching the residues, then burning, returning the filtrate to the second step for recycling, filtering the solid precipitation layer, returning the obtained filtrate to the second step for recycling, and then washing the filter cake;
step six: and drying the filter cake obtained in the fifth step to obtain a purified anhydrous calcium sulfate product.
In the first step, the industrial solid waste gypsum is one of phosphogypsum, salt gypsum, desulfurized gypsum, fluorgypsum, titanium gypsum or citric acid gypsum.
In the second step, the mass fraction of the hydrochloric acid is 9-15%; the solid-to-liquid ratio (kg/L) of the solid waste gypsum powder to the hydrochloric acid is 1 (1-5).
In the second step, the organic solvent is one or a combination of two of monobutyl phosphate, dibutyl phosphate, tributyl phosphate, P-204{ di (2-ethylhexyl) phosphate }, P-507 (2-ethylhexyl phosphate mono-2-ethylhexyl), diethyl phosphate and triisobutyl phosphate; the solid-liquid ratio (kg/L) of the solid waste gypsum powder to the organic solvent is 1: (1-5).
In the second step, the stirring speed is 300-600 r/min.
And in the sixth step, the filter cake is repeatedly washed with hot water for three times, and is washed with ethanol for one time, and the finished filter cake is dried by air blowing at 40-80 ℃ for 1-6 hours to obtain the anhydrous calcium sulfate powder.
The invention has the beneficial effects that: by adopting a liquid phase chemical method, the conversion of the calcium sulfate dihydrate in the gypsum waste residue to the anhydrous calcium sulfate is directly realized in the purification process of the industrial solid waste gypsum, so that the high-temperature calcination process is omitted, and the energy consumption is greatly reduced. The purified anhydrous calcium sulfate has the advantages of high purity, good whiteness, uniform particle size and the like, and has wide industrial application prospect. After the industrial byproduct gypsum is treated by the method, the obtained anhydrous calcium sulfate has extremely high additional value, and a new way is opened up for the comprehensive utilization of the industrial solid waste gypsum.
Description of the drawings:
the invention is described in further detail below with reference to the figures and the detailed description.
Figure 1 is the XRD pattern of calcium sulfate anhydrate prepared in example 1.
Fig. 2 is an SEM image of anhydrous calcium sulfate prepared in example 1.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention clearer and to make the skilled in the art better understand the present invention, the present invention is further illustrated by the following examples, which are only used for illustrative purposes and do not limit the scope of the present invention. The test methods in the following examples, which are not specified under specific conditions, are generally carried out under conventional conditions.
Example 1:
drying, crushing, grinding and sieving the phosphogypsum to obtain a dry material (screen residue is enriched and calcined into a glass building material) with the granularity of less than 100 meshes, and then mixing the dry material with hydrochloric acid according to the solid-to-liquid ratio (kg/L) of 2: 3. Wherein the mass fraction of the hydrochloric acid is 9 percent. Then adding diethyl phosphate into the mixture, wherein the solid-to-liquid ratio (kg/L) of the diethyl phosphate to the raw material phosphogypsum powder is 1: 1. And finally, stirring the mixture at the rotating speed of 300 r/min and gradually heating, continuing stirring and reacting for 2 hours after the temperature is raised to 70 ℃, standing the mixture after the reaction is finished to separate the mixture into layers, and separating solid and liquid, wherein the upper layer is a liquid phase layer containing impurities, and the lower layer is a solid precipitation layer of purified gypsum. And then separating the solid-liquid mixture, wherein the impurity-containing liquid phase layer and the solid precipitation layer are separated respectively. Filtering the obtained impurity-containing liquid phase layer to remove residues, enriching the residues, then burning, and returning the filtrate to continuously dissolve the phosphogypsum. The solid precipitate layer was filtered and the filtrate was returned for reuse. And then washing the filter cake, repeatedly washing the filter cake for three times by hot water, washing the filter cake once by ethanol, and then carrying out forced air drying on the finished filter cake for 6 hours at the temperature of 80 ℃ to obtain the anhydrous calcium sulfate powder.
Example 2:
drying, crushing, grinding and sieving the phosphogypsum to obtain a dry material (screen residue is enriched and calcined into a glass building material) with the granularity of less than 100 meshes, and then mixing the dry material with hydrochloric acid according to the solid-to-liquid ratio (kg/L) of 2: 3. Wherein the mass fraction of the hydrochloric acid is 9 percent. Then monobutyl phosphate is added into the mixture, and the solid-to-liquid ratio (kg/L) of the monobutyl phosphate to the raw material phosphogypsum powder is 1: 1. And finally, stirring the mixture at the rotating speed of 300 r/min and gradually heating, continuing stirring and reacting for 2 hours after the temperature is raised to 80 ℃, standing the mixture after the reaction is finished to separate the mixture into layers, and separating solid and liquid, wherein the upper layer is a liquid phase layer containing impurities, and the lower layer is a solid precipitation layer of purified gypsum. And then separating the solid-liquid mixture, wherein the impurity-containing liquid phase layer and the solid precipitation layer are separated respectively. Filtering the obtained impurity-containing liquid phase layer to remove residues, enriching the residues, then burning, and returning the filtrate to continuously dissolve the phosphogypsum. The solid precipitate layer was filtered and the filtrate was returned for reuse. And then washing the filter cake, repeatedly washing the filter cake for three times by hot water, washing the filter cake once by ethanol, and then carrying out forced air drying on the finished filter cake for 6 hours at the temperature of 80 ℃ to obtain the anhydrous calcium sulfate powder.
Example 3:
drying, crushing, grinding and sieving the phosphogypsum to obtain a dry material (screen residue is enriched and calcined into a glass building material) with the granularity of less than 100 meshes, and then mixing the dry material with hydrochloric acid according to the solid-to-liquid ratio (kg/L) of 1: 3. Wherein the mass fraction of the hydrochloric acid is 11 percent. And then adding monobutyl phosphate and diethyl phosphate into the mixture, wherein the solid-to-liquid ratio (kg/L) of the monobutyl phosphate and the diethyl phosphate to the raw material phosphogypsum powder is 1:2, and the volume ratio of the monobutyl phosphate to the diethyl phosphate is 1: 1. And finally stirring the mixture at the rotating speed of 300 r/min and gradually heating, continuing stirring and reacting for 2 hours after the temperature is raised to 90 ℃, standing the mixture after the reaction is finished to separate the mixture into layers, and separating solid and liquid, wherein the upper layer is a liquid phase layer containing impurities, and the lower layer is a solid precipitation layer of purified gypsum. And then separating the solid-liquid mixture, wherein the impurity-containing liquid phase layer and the solid precipitation layer are separated respectively. Filtering the obtained impurity-containing liquid phase layer to remove residues, enriching the residues, then burning, returning the filtrate to continuously dissolve the phosphogypsum, filtering the solid precipitation layer, and returning the obtained filtrate for reuse. And then washing the filter cake, repeatedly washing the filter cake for three times by hot water, washing the filter cake once by ethanol, and then carrying out forced air drying on the finished filter cake for 6 hours at the temperature of 80 ℃ to obtain the anhydrous calcium sulfate powder.
Example 4:
drying, crushing, grinding and sieving the salt gypsum to obtain dry materials (screen residue is enriched and calcined into glass building materials) with the granularity less than 100 meshes, and then mixing the dry materials with hydrochloric acid according to the solid-to-liquid ratio (kg/L) of 2: 3. Wherein the mass fraction of the hydrochloric acid is 9 percent. Then, monobutyl phosphate is added into the mixture, and the solid-to-liquid ratio (kg/L) of the monobutyl phosphate to the raw material salt gypsum powder is 1: 1. And finally, stirring the mixture at the rotating speed of 300 r/min and gradually heating, continuing stirring and reacting for 2 hours after the temperature is raised to 70 ℃, standing the mixture after the reaction is finished to separate the mixture into layers, and separating solid and liquid, wherein the upper layer is a liquid phase layer containing impurities, and the lower layer is a solid precipitation layer of purified gypsum. And then separating the solid-liquid mixture, wherein the impurity-containing liquid phase layer and the solid precipitation layer are separated respectively. Filtering the obtained impurity-containing liquid phase layer to remove residues, enriching the residues, then carrying out incineration treatment, returning the filtrate to continuously dissolve the salt gypsum, filtering the solid precipitation layer, and returning the obtained filtrate for reuse. And then washing the filter cake, repeatedly washing the filter cake for three times by hot water, washing the filter cake once by ethanol, and then carrying out forced air drying on the finished filter cake for 6 hours at the temperature of 80 ℃ to obtain the anhydrous calcium sulfate powder.
Example 5:
drying, crushing, grinding and sieving the salt gypsum to obtain dry materials (screen residue is enriched and calcined into glass building materials) with the granularity less than 100 meshes, and then mixing the dry materials with hydrochloric acid according to the solid-to-liquid ratio (kg/L) of 1: 3. Wherein the mass fraction of the hydrochloric acid is 11 percent. Diethyl phosphate was then added to the mixture in a solid-to-liquid ratio (kg/L) of 1:2 with the starting salt gypsum powder. And finally, stirring the mixture at the rotating speed of 300 r/min and gradually heating, continuing stirring and reacting for 2 hours after the temperature is raised to 80 ℃, standing the mixture after the reaction is finished to separate the mixture into layers, and separating solid and liquid, wherein the upper layer is a liquid phase layer containing impurities, and the lower layer is a solid precipitation layer of purified gypsum. And then separating the solid-liquid mixture, wherein the impurity-containing liquid phase layer and the solid precipitation layer are separated respectively. Filtering the obtained impurity-containing liquid phase layer to remove residues, enriching the residues, then carrying out incineration treatment, returning the filtrate to continuously dissolve the salt gypsum, filtering the solid precipitation layer, and returning the obtained filtrate for reuse. And then washing the filter cake, repeatedly washing the filter cake for three times by hot water, washing the filter cake once by ethanol, and then carrying out forced air drying on the finished filter cake for 6 hours at the temperature of 80 ℃ to obtain the anhydrous calcium sulfate powder.
Example 6:
drying, crushing, grinding and sieving the salt gypsum to obtain dry materials (screen residue is enriched and calcined into glass building materials) with the granularity less than 100 meshes, and then mixing the dry materials with hydrochloric acid according to the solid-to-liquid ratio (kg/L) of 1: 3. Wherein the mass fraction of the hydrochloric acid is 11 percent. Then, monobutyl phosphate and diethyl phosphate are added into the mixture, the solid-to-liquid ratio (kg/L) of the monobutyl phosphate and the diethyl phosphate to the raw material salt gypsum powder is 1:2, and the volume ratio of the monobutyl phosphate to the diethyl phosphate is 1: 1. And finally stirring the mixture at the rotating speed of 300 r/min and gradually heating, continuing stirring and reacting for 2 hours after the temperature is raised to 90 ℃, standing the mixture after the reaction is finished to separate the mixture into layers, and separating solid and liquid, wherein the upper layer is a liquid phase layer containing impurities, and the lower layer is a solid precipitation layer of purified gypsum. And then separating the solid-liquid mixture, wherein the impurity-containing liquid phase layer and the solid precipitation layer are separated respectively. Filtering the obtained impurity-containing liquid phase layer to remove residues, enriching the residues, then carrying out incineration treatment, returning the filtrate to continuously dissolve the salt gypsum, filtering the solid precipitation layer, and returning the obtained filtrate for reuse. And then washing the filter cake, repeatedly washing the filter cake for three times by hot water, washing the filter cake once by ethanol, and then carrying out forced air drying on the finished filter cake for 6 hours at the temperature of 80 ℃ to obtain the anhydrous calcium sulfate powder.
Example 7:
drying, crushing, grinding and sieving the desulfurized gypsum to obtain a dry material (screen residue is enriched and calcined into a glass building material) with the granularity of less than 100 meshes, and then mixing the dry material with hydrochloric acid according to the solid-to-liquid ratio (kg/L) of 2: 3. Wherein the mass fraction of the hydrochloric acid is 9 percent. Then, monobutyl phosphate is added into the mixture, and the solid-to-liquid ratio (kg/L) of the monobutyl phosphate to the raw material desulfurized gypsum powder is 1: 1. And finally, stirring the mixture at the rotating speed of 300 r/min and gradually heating, continuing stirring and reacting for 2 hours after the temperature is raised to 70 ℃, standing the mixture after the reaction is finished to separate the mixture into layers, and separating solid and liquid, wherein the upper layer is a liquid phase layer containing impurities, and the lower layer is a solid precipitation layer of purified gypsum. And then separating the solid-liquid mixture, wherein the impurity-containing liquid phase layer and the solid precipitation layer are separated respectively. Filtering the obtained impurity-containing liquid phase layer to remove residues, enriching the residues, then carrying out incineration treatment, returning the filtrate to continuously dissolve the desulfurized gypsum, filtering the solid precipitation layer, and returning the obtained filtrate for reuse. And then washing the filter cake, repeatedly washing the filter cake for three times by hot water, washing the filter cake once by ethanol, and then carrying out forced air drying on the finished filter cake for 6 hours at the temperature of 80 ℃ to obtain the anhydrous calcium sulfate powder.
Example 8:
drying, crushing, grinding and sieving the desulfurized gypsum to obtain a dry material (screen residue is enriched and calcined into a glass building material) with the granularity of less than 100 meshes, and then mixing the dry material with hydrochloric acid according to the solid-to-liquid ratio (kg/L) of 1: 3. Wherein the mass fraction of the hydrochloric acid is 11 percent. And adding dibutyl phosphate into the mixture, wherein the solid-to-liquid ratio (kg/L) of dibutyl phosphate to the raw material desulfurized gypsum powder is 1: 2. And finally, stirring the mixture at the rotating speed of 300 r/min and gradually heating, continuing stirring and reacting for 2 hours after the temperature is raised to 80 ℃, standing the mixture after the reaction is finished to separate the mixture into layers, and separating solid and liquid, wherein the upper layer is a liquid phase layer containing impurities, and the lower layer is a solid precipitation layer of purified gypsum. And then separating the solid-liquid mixture, wherein the impurity-containing liquid phase layer and the solid precipitation layer are separated respectively. Filtering the obtained impurity-containing liquid phase layer to remove residues, enriching the residues, then carrying out incineration treatment, returning the filtrate to continuously dissolve the desulfurized gypsum, filtering the solid precipitation layer, and returning the obtained filtrate for reuse. And then washing the filter cake, repeatedly washing the filter cake for three times by hot water, washing the filter cake once by ethanol, and then carrying out forced air drying on the finished filter cake for 6 hours at the temperature of 80 ℃ to obtain the anhydrous calcium sulfate powder.
Example 9:
drying, crushing, grinding and sieving the desulfurized gypsum to obtain a dry material (screen residue is enriched and calcined into a glass building material) with the granularity of less than 100 meshes, and then mixing the dry material with hydrochloric acid according to the solid-to-liquid ratio (kg/L) of 1: 3. Wherein the mass fraction of the hydrochloric acid is 11 percent. And then adding monobutyl phosphate and diethyl phosphate into the mixture, wherein the solid-to-liquid ratio (kg/L) of the monobutyl phosphate and the diethyl phosphate to the raw material desulfurized gypsum powder is 1:2, and the volume ratio of the monobutyl phosphate to the diethyl phosphate is 1: 1. And finally stirring the mixture at the rotating speed of 300 r/min and gradually heating, continuing stirring and reacting for 2 hours after the temperature is raised to 90 ℃, standing the mixture after the reaction is finished to separate the mixture into layers, and separating solid and liquid, wherein the upper layer is a liquid phase layer containing impurities, and the lower layer is a solid precipitation layer of purified gypsum. And then separating the solid-liquid mixture, wherein the impurity-containing liquid phase layer and the solid precipitation layer are separated respectively. Filtering the obtained impurity-containing liquid phase layer to remove residues, enriching the residues, then carrying out incineration treatment, returning the filtrate to continuously dissolve the desulfurized gypsum, filtering the solid precipitation layer, and returning the obtained filtrate for reuse. And then washing the filter cake, repeatedly washing the filter cake for three times by hot water, washing the filter cake once by ethanol, and then carrying out forced air drying on the finished filter cake for 6 hours at the temperature of 80 ℃ to obtain the anhydrous calcium sulfate powder.
The foregoing summary and structure are provided to explain the principles, general features, and advantages of the product and to enable others skilled in the art to understand the invention. The foregoing examples and description have been presented to illustrate the principles of the invention and are intended to provide various changes and modifications within the spirit and scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.
Claims (7)
1. The method for preparing anhydrous calcium sulfate from industrial solid waste gypsum is characterized by comprising the following steps:
the method comprises the following steps: drying, crushing, grinding and sieving industrial solid waste gypsum to obtain powder with the particle size of less than 100 meshes for later use, enriching screen residues, and calcining the powder into a glass building material;
step two: mixing the powder with the granularity of less than 100 meshes obtained in the step one with hydrochloric acid, adding an organic solvent, stirring, heating, and continuing to react for 1-6 hours after the temperature of the mixture is raised to 70-90 ℃;
step three: standing the suspension obtained in the step two to separate solid from liquid, wherein the upper layer is a liquid phase layer containing impurities, and the lower layer is a solid precipitation layer of purified gypsum;
step four: separating the solid-liquid mixture obtained in the step three, wherein a liquid phase layer and a solid precipitate are respectively separated;
step five: filtering the impurity-containing liquid phase layer obtained in the fourth step to remove residues, enriching the residues, then burning, returning the filtrate to the second step for recycling, filtering the solid precipitation layer, returning the obtained filtrate to the second step for recycling, and then washing the filter cake;
step six: and drying the filter cake obtained in the fifth step to obtain a purified anhydrous calcium sulfate product.
2. The method for preparing anhydrous calcium sulfate from industrial solid waste gypsum according to claim 1, which is characterized by comprising the following steps: in the first step, the industrial solid waste gypsum is one of phosphogypsum, salt gypsum, desulfurized gypsum, fluorgypsum, titanium gypsum or citric acid gypsum.
3. The method for preparing anhydrous calcium sulfate from industrial solid waste gypsum according to claim 1, which is characterized by comprising the following steps: in the second step, the mass fraction of the hydrochloric acid is 9-15%.
4. The method for preparing anhydrous calcium sulfate from industrial solid waste gypsum according to claim 1, which is characterized by comprising the following steps: in the second step, the solid-to-liquid ratio (kg/L) of the solid waste gypsum powder to the hydrochloric acid is 1 (1-5).
5. The method for preparing anhydrous calcium sulfate from industrial solid waste gypsum according to claim 1, which is characterized by comprising the following steps: in the second step, the organic solvent is one or a combination of two of monobutyl phosphate, dibutyl phosphate, tributyl phosphate, P-204{ di (2-ethylhexyl) phosphate }, P-507 (2-ethylhexyl phosphate mono-2-ethylhexyl), diethyl phosphate and triisobutyl phosphate; the solid-liquid ratio (kg/L) of the solid waste gypsum powder to the organic solvent is 1: (1-5).
6. The method for preparing anhydrous calcium sulfate from industrial solid waste gypsum according to claim 1, which is characterized by comprising the following steps: in the second step, the stirring speed is 300-600 r/min.
7. The method for preparing anhydrous calcium sulfate from industrial solid waste gypsum according to claim 1, which is characterized by comprising the following steps: and in the sixth step, the filter cake is repeatedly washed with hot water for three times, and is washed with ethanol for one time, and the finished filter cake is dried by air blowing at 40-80 ℃ for 1-6 hours to obtain the anhydrous calcium sulfate powder.
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN113753936A (en) * | 2021-09-16 | 2021-12-07 | 浙江钙宝新材料有限公司 | Method for preparing calcium sulfate nanospheres from industrial solid waste gypsum |
| CN113830814A (en) * | 2021-09-16 | 2021-12-24 | 浙江钙宝新材料有限公司 | Method for preparing calcium sulfate nano-rods from industrial solid waste gypsum |
| CN115636431A (en) * | 2022-11-09 | 2023-01-24 | 浙江钙宝新材料有限公司 | Method for preparing anhydrous calcium sulfate and calcium sulfate dihydrate from industrial solid waste gypsum |
| CN115924952A (en) * | 2022-12-14 | 2023-04-07 | 西南科技大学 | Anhydrite powder, gypsum whisker and preparation method thereof |
| CN117886526A (en) * | 2024-01-26 | 2024-04-16 | 湖北省长江资源循环利用及装备创新中心有限公司 | Method for preparing II-type anhydrous gypsum and building gypsum from phosphogypsum |
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| CN105859167A (en) * | 2015-01-21 | 2016-08-17 | 中国科学院过程工程研究所 | Method for preparing white and high-purity anhydrous calcium sulfate by phosphogypsum |
| CN107190325A (en) * | 2017-05-09 | 2017-09-22 | 武汉理工大学 | A kind of method that utilization industrial by-product ardealite prepares anhydrous calcium sulfate whisker |
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| CN105859167A (en) * | 2015-01-21 | 2016-08-17 | 中国科学院过程工程研究所 | Method for preparing white and high-purity anhydrous calcium sulfate by phosphogypsum |
| CN107190325A (en) * | 2017-05-09 | 2017-09-22 | 武汉理工大学 | A kind of method that utilization industrial by-product ardealite prepares anhydrous calcium sulfate whisker |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113753936A (en) * | 2021-09-16 | 2021-12-07 | 浙江钙宝新材料有限公司 | Method for preparing calcium sulfate nanospheres from industrial solid waste gypsum |
| CN113830814A (en) * | 2021-09-16 | 2021-12-24 | 浙江钙宝新材料有限公司 | Method for preparing calcium sulfate nano-rods from industrial solid waste gypsum |
| CN115636431A (en) * | 2022-11-09 | 2023-01-24 | 浙江钙宝新材料有限公司 | Method for preparing anhydrous calcium sulfate and calcium sulfate dihydrate from industrial solid waste gypsum |
| CN115924952A (en) * | 2022-12-14 | 2023-04-07 | 西南科技大学 | Anhydrite powder, gypsum whisker and preparation method thereof |
| CN115924952B (en) * | 2022-12-14 | 2024-05-03 | 西南科技大学 | Anhydrite powder, gypsum whisker and preparation method thereof |
| CN117886526A (en) * | 2024-01-26 | 2024-04-16 | 湖北省长江资源循环利用及装备创新中心有限公司 | Method for preparing II-type anhydrous gypsum and building gypsum from phosphogypsum |
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